Very Heavy Rains At Sunrise

An area of thunderstorms developed west of the Tucson Mountains between 3 and 4 am this morning. The storms have been slow moving and producing very heavy rainfall. The map of rainfall reports from past 24-hours (above) from the western section of the ALERT network, shows 3 reports over 2 inches and 1 over 3 inches. At Vahala Park, 1.61" of the 3 inch plus rainfall has fallen during the past hour! Caution needed for morning drivers west of the Tucson Mountains. The composite radar image of the situation at 6:30 am is shown below. When I walked, there were occasional lightning flashes from the west to the southwest.

Yesterday afternoon, with much of the pesky layer of CIN gone, storms formed over the mountains by lunch hour and coverage increased rapidly. Movement was generally toward the northwest, but individual cells were moving helter skelter. By 5:30 pm the heaviest storm activity was off in the southwest part of the state, between Quartzsite and Yuma. At 6 pm last evening almost 80% of the ALERT sites had reported rainfall - but note in the top image that the convective cells mostly managed to miss the core downtown area. We had a strong outflow from the south here (estimated at 40 to 50 mph) just after 3 pm MST, but no significant rain other than light showers from storm debris clouds - total here was only 0.03".